The present invention generally relates to thin film forming apparatus, and more particularly to a thin film forming apparatus for forming a thin film on a substrate made of a material less resistant to heat than glass, which is applied to the manufacture of plastic lenses, large scale integrated circuits, etc.
There is a conventional thin film forming apparatus for forming a thin film with good adhesion and uniform density on a substrate made of a material such as plastic which is less resistant to heat than glass. Such a conventional apparatus provides a resultant film showing good characteristics, but usually employs a common vaporization unit for vaporizing a source material into vapor before depositing the source material on the substrate. With the common vaporization unit used in the conventional thin film forming apparatus, the kind of source materials selectable and the combination of source materials usable are limited, and the quantity of source material vapors to be deposited on the substrate is difficult to control to obtain a desired thin-film circuit or a desired thin film lense. Also the conventional thin film forming apparatus employing such a common vaporization unit usually has a problem in that the substrate on which the source material is deposited has a relatively great area. That is, it is difficult for the conventional apparatus to provide a resultant film formed on a substrate having a relatively great area with a uniform density.